SIMPLE SOLUTIONS

BUS_READ_IVAR(9FREEBSD) - man page online | system kernel interfaces

Manipulate bus-specific device instance variables.

Chapter
June 16, 1998
BUS_READ_IVAR(9)                  BSD Kernel Developer's Manual                  BUS_READ_IVAR(9)

NAME

BUS_READ_IVAR, BUS_WRITE_IVAR — manipulate bus-specific device instance variables

SYNOPSIS

#include <sys/param.h> #include <sys/bus.h> int BUS_READ_IVAR(device_t dev, device_t child, int index, uintptr_t *result); int BUS_WRITE_IVAR(device_t dev, device_t child, int index, uintptr_t value);

DESCRIPTION

These two methods manage a bus specific set of instance variables of a child device. The intention is that each different type of bus defines a set of appropriate instance variables (such as ports and irqs for ISA bus etc.) This information could be given to the child device as a struct but that makes it hard for a bus to add or remove variables without forcing an edit and recompile for all drivers which may not be possible for vendor supplied binary drivers.

RETURN VALUES

Zero is returned on success, otherwise an appropriate error is returned.

SEE ALSO

device(9), driver(9)

AUTHORS

This manual page was written by Doug Rabson.
BSD June 16, 1998 BSD
This manual Reference Other manuals
BUS_READ_IVAR(9freebsd) referred by BUS_WRITE_IVAR(9freebsd) | device_get_ivars(9freebsd) | device_set_ivars(9freebsd)
refer to device(9freebsd) | driver(9freebsd)